This invention relates to the general field of vehicle equipment. It concerns more particularly a new device for actuating vehicle anticrash lights based on a predetermined braking threshold, it also relates to an original method in order to actuate the anticrash lights using this device, as well as a material enabling to programme and to calibrate the said device.
Emergency braking warning devices using inertia sensors mounted on the vehicle are already known (automobile, motorbike or heavy vehicle) to trigger the anticrash lights automatically based on a predetermined braking threshold in order to warn the other drivers that the braking system of the vehicle has been initiated, with the potential inherent risk.
Generally, the known devices are not completely satisfactory, since their structure is complex or lacks accuracy and reliability.
In particular, the document DE-U-2 961 75 27 relates to an automobile equipment that implements automatically the anticrash lights of the vehicle when the xe2x80x98ABSxe2x80x99 or xe2x80x98AIRBAGxe2x80x99 system has been actuated, i.e. in case of emergency braking or collision.
This device can only operate in the presence of an xe2x80x98ABSxe2x80x99 or an xe2x80x98AIRBAGxe2x80x99 system and it cannot therefore be mounted on all types of vehicle.
Besides, the data from the safety equipment already available on the vehicle (ABS or AIRBAG) is used to trigger the anticrash lights. Triggering the anticrash lights is therefore only an accessory of the main safety equipment; this triggering can be hardly adjusted independently of the adjustments foreseen on the main pieces of safety equipment, and the operation of the triggering system of the anticrash lights can be altered by the presence of the main twin equipment.
This invention suggests a new material and a new method enabling to better meet the requirements set in that field, in particular in terms of endurance, reliability and accuracy.
The emergency braking warning system according to this invention consists of a printed circuit whereon are implanted, notably, a voltage regulator/stabiliser assembly, a two-way digital inertia sensor, a microprocessor and power control elements. The voltage regulator/stabiliser assembly is connected to the vehicle battery and powers the two-way digital inertia sensor and the microprocessor, which microprocessor is adapted to manage the data coming from the said sensor and is connected to the power controls (transistors or relays) interposed on the circuits of the right and left flashers to enable the simultaneous triggering of the said flashers when the programmed braking threshold is exceeded.
This device has the form of an electronic assembly housed in a casing that only calls for connection with the vehicle battery and with the circuits of the right and left flashers; it is a completely stand-alone device of simple, reliable design and straightforward to install on any type of vehicle.
This emergency braking warning device comprises preferably means that enable the triggering of a sound signal simultaneously to the triggering of the anticrash lights. Still advantageously, it comprises means that enable to detect the initiation of the vehicle windscreen wipers, whereas these means of detection are connected to the microprocessor in order, when the windscreen wipers are operating, to enable the said microprocessor to trigger the vehicle anticrash lights based on a reduced braking threshold.
The implementation method of this device is characterised in that it consists:
in the microprocessor recording the successive digital values Vn delivered by the two-way digital inertia sensor mounted on the vehicle,
in the microprocessor calculating the difference between each value Vn and the value Vnxe2x88x92x that was delivered by the inertia sensor a moment x previously,
in the microprocessor performing a comparison between the value Vnxe2x88x92Vnxe2x88x92x and a predefined threshold value A, corresponding to a braking threshold value, and
in the microprocessor triggering the simultaneous control of the right and left flashers, in the case when the difference Vnxe2x88x92Vnxe2x88x92x is greater than the threshold value A.
This method ensures permanent and automatic re-calibration of the material. It enables to use reduced accuracy when implanting the sensor in the vehicle, as regards its direction and its angle, it also enables to filter the data delivered by the sensor in order to trigger the anticrash lights only when appropriate.
According to another feature, the method according to this invention consists in performing full-scale calibration of the inertia sensor before installing the material on the vehicle. This calibration is carried out while recording the digital value of the sensor when its active line is in horizontal position, at zero speed, whereas this digital value corresponds to the value delivered by the affected sensor for a zero acceleration (0 g), and while recording the digital value of the sensor when its active line is in vertical position, at zero speed, whereas this digital value corresponds to the value delivered by the affected sensor for a 1 g acceleration, since these operations enable to obtain the full-scale digital value of the sensor between 0 g and 1 g, to deduce the digital value corresponding to the scale unit and to integrate this digital value in the programming of the microprocessor.
This invention also relates to a material suited to the programming and the calibration of the emergency braking warning device, before its installation in the vehicle.
According to the invention, this material comprises a seat for the reception and the locking in position of at least one printed circuit whereon is implanted the emergency braking warning device, whereas the said seat comprises a set of pins arranged to contact certain parts or elements of the printed circuit, in order to ensure the programming of the microprocessor by appropriate computerised means. This seat is hinged on a base in order to enable horizontal positioning of the active line of the sensor to record the digital value delivered for a zero acceleration (0 g) and to enable vertical positioning of the active line of the sensor to record the digital value delivered for a 1 g, in order to programme the microprocessor based on the calibration of the sensor.